I think the airport line is a joke. If you don’t start at the main station you’re getting nowhere in time.
There is a connection in Sanzhong, where you need to wait for the commuter train up to 20-25 minutes or so, than you can change at the industry park or the hospital to get on the ‘airport express’. Completely useless. I wonder why they didn’t make the connecting in Sanzhong directly onto the airport express.